Why did Instagram remove the like count on posts?

The main user goal of instagram or any other social platform is allow people to share content with their friends either via posts or stories and connect with more people. They want to increase engagement on the platform so that they can earn revenue from ads. 

One criticism that these platforms have received in the recent past is that these like numbers put a lot of pressure on people making them very anxious and do not post more often. They want to encourage people to post more and not worry about the likes they get.

Removing likes will also encourage more people to comment on posts if they want their engagement to be more visible to all.

Comments will also help Facebook/Instagram, brands, influencers as well as general audience get more insights on the other users. Brands and influencers can get better feedback through comments than through just like numbers. 

Removing the number of likes will reduce influencer power and brands may focus more on paid advertising. Right now most brands try to promote their products through influencers who get a huge number of likes. By removing these likes, you are reducing their power since it would be difficult to find the right influencers who are getting more eyeballs compared to others. 

Also a lot of users end up buying likes and thus mess with engagement algorithm of these platforms and users don't see relevant content impacting the stickiness of the platform. Removing the number of likes will discourage that behavior. 

Ranking these Reasons 

According to me I think the top reason for instagram to implement this is to encourage people to post more and focus on sharing aspect rather than on the number of likes reducing social anxieties and pressure. 

I would rank - urging people to comment more - as the second most important reason since instagram wants better insights from users about what kind of content they would like to see. 

The other reasons are not as significant as these two reasons.